动态调试elf文件的几种方法
0x01 ida动态调试
0x02 gdb动态调试
gdb <program> //启动quit //结束
run：简写为r，运行调试程序，直到断点处stepi：简写为s，执行一条指令，步入函数nexti：简写为n，执行一条指令，步过函数continue：简写为c，继续执行until：在一个循环体内部单步跟踪的时候，可以通过until命令跳出循环until+行号：运行至某行
break *address：简写b *address，设置断点info breakpoints：简写为info b，查看断点delete *address：删除断点disable *address：暂停断点enable *address：开启断点delete breakpoints：删除所有断点
info register：简写为info r，查看寄存器x/countFormatSize addr：以指定格式Format打印地址address处的指定大小size、指定数量count的对象Size：b（字节）、h（半字）、w（字）、g（8字节）Format：o（八进制）、d（十进制）、x（十六进制）、u（无符号十进制）、t（二进制）、f（浮点数）、a（地 址）、i(指令)、c（字符）、s（字符串）backtrace：打印函数调用栈回溯set $reg=value：修改寄存器set *(type*)(address)=value：修改内存地址addr为value
0x03 radare2动态调试
$ r2 ./e3dd9674429f4ce1a25c08ea799fc027[0x00400660]> aaa[x] Analyze all flags starting with sym. and entry0 (aa)[x] Analyze function calls (aac)[x] Analyze len bytes of instructions for references (aar)[x] Check for vtables[x] Type matching analysis for all functions (aaft)[x] Propagate noreturn information[x] Use -AA or aaaa to perform additional experimental analysis.
r2 -A ./program来直接分析程序$ r2 -A ./e3dd9674429f4ce1a25c08ea799fc027[x] Analyze all flags starting with sym. and entry0 (aa)[x] Analyze function calls (aac)[x] Analyze len bytes of instructions for references (aar)[x] Check for vtables[x] Type matching analysis for all functions (aaft)[x] Propagate noreturn information[x] Use -AA or aaaa to perform additional experimental analysis.
iI命令可以提供很多有用的信息iIarch x86baddr 0x400000binsz 9449bintype elfbits 64canary trueclass ELF64compiler GCC: (Ubuntu 5.4.1-2ubuntu1~14.04) 5.4.1 20160904 GCC: (Ubuntu 4.8.4-2ubuntu1~14.04.3) 4.8.4crypto falseendian littlehavecode trueintrp /lib64/ld-linux-x86-64.so.2laddr 0x0lang clinenum truelsyms truemachine AMD x86-64 architecturemaxopsz 16minopsz 1nx trueos linuxpcalign 0pic falserelocs truerelro partialrpath NONEsanitiz falsestatic falsestripped falsesubsys linuxva true
ii和iE命令来看下程序的导入和导出函数，从而能够更好的了解程序实现的功能ii[Imports]nth vaddr bind type lib name―――――――――――――――――――――――――――――――――――――1 0x004005c0 GLOBAL FUNC remove2 0x004005d0 GLOBAL FUNC fclose3 0x004005e0 GLOBAL FUNC strlen4 0x004005f0 GLOBAL FUNC __stack_chk_fail5 0x00400600 GLOBAL FUNC fputc6 0x00400610 GLOBAL FUNC __libc_start_main7 0x00400620 GLOBAL FUNC fprintf8 0x00400630 WEAK NOTYPE __gmon_start__9 0x00400640 GLOBAL FUNC fseek10 0x00400650 GLOBAL FUNC fopeniE[Exports]nth paddr vaddr bind type size lib name――――――――――――――――――――――――――――――――――――――――――――――――――――――45 0x00000960 0x00400960 GLOBAL FUNC 2 __libc_csu_fini49 0x000010e0 0x006010e0 GLOBAL OBJ 44 t50 ---------- 0x0060120c GLOBAL NOTYPE 0 _edata51 0x00001160 0x00601160 GLOBAL OBJ 172 p53 0x00000964 0x00400964 GLOBAL FUNC 0 _fini58 0x00001080 0x00601080 GLOBAL NOTYPE 0 __data_start61 0x00001088 0x00601088 GLOBAL OBJ 0 __dso_handle62 0x00000970 0x00400970 GLOBAL OBJ 4 _IO_stdin_used63 0x000008f0 0x004008f0 GLOBAL FUNC 101 __libc_csu_init64 ---------- 0x00601210 GLOBAL NOTYPE 0 _end65 0x00000660 0x00400660 GLOBAL FUNC 0 _start67 0x000010a0 0x006010a0 GLOBAL OBJ 33 s68 0x00001120 0x00601120 GLOBAL OBJ 44 u69 ---------- 0x0060120c GLOBAL NOTYPE 0 __bss_start70 0x00000756 0x00400756 GLOBAL FUNC 407 main73 ---------- 0x00601210 GLOBAL OBJ 0 __TMC_END__75 0x00000590 0x00400590 GLOBAL FUNC 0 _init
afl命令查看程序存在的函数，从而找到main函数，定位到对应的位置，查看反汇编代码[0x00400660]> afl0x00400660 1 41 entry00x00400610 1 6 sym.imp.__libc_start_main0x00400690 4 50 -> 41 sym.deregister_tm_clones0x004006d0 4 58 -> 55 sym.register_tm_clones0x00400710 3 28 sym.__do_global_dtors_aux0x00400730 4 38 -> 35 entry.init00x00400960 1 2 sym.__libc_csu_fini0x00400964 1 9 sym._fini0x004008f0 4 101 sym.__libc_csu_init0x00400756 12 407 main0x00400590 3 26 sym._init0x00400630 1 6 loc.imp.__gmon_start__0x004005c0 1 6 sym.imp.remove0x004005d0 1 6 sym.imp.fclose0x004005e0 1 6 sym.imp.strlen0x004005f0 1 6 sym.imp.__stack_chk_fail0x00400600 1 6 sym.imp.fputc0x00400620 1 6 sym.imp.fprintf0x00400640 1 6 sym.imp.fseek0x00400650 1 6 sym.imp.fopen
axt命令来查看函数调用[0x00400660]> axt mainentry0 0x40067d [DATA] mov rdi, main
s命令定位到main函数，pdf命令来查看函数的反汇编代码，s命令后可以加地址或者函数名[]> s main; DATA XREF from entry0 @ 0x40067d┌ 407: int main (int argc, char **argv, char **envp);│ ; var int64_t var_40h @ rbp-0x40│ ; var int64_t var_3ch @ rbp-0x3c│ ; var file*stream @ rbp-0x38│ ; var char *filename @ rbp-0x30│ ; var int64_t var_28h @ rbp-0x28│ ; var int64_t var_24h @ rbp-0x24│ ; var int64_t canary @ rbp-0x18│ 0x00400756 55 push rbp│ 0x00400757 4889e5 mov rbp, rsp│ 0x0040075a 53 push rbx│ 0x0040075b 4883ec38 sub rsp, 0x38│ 0x0040075f 64488b042528. mov rax, qword fs:[0x28]│ 0x00400768 488945e8 mov qword [canary], rax│ 0x0040076c 31c0 xor eax, eax│ 0x0040076e c745c0000000. mov dword [var_40h], 0│ ; CODE XREF from main @ 0x4007c5│ ┌─> 0x00400775 8b45c0 mov eax, dword [var_40h]│ ╎ 0x00400778 4863d8 movsxd rbx, eax│ ╎ 0x0040077b bfa0106000 mov edi, obj.s ; 0x6010a0 ; "c61b68366edeb7bdce3c6820314b7498" ; const char *s│ ╎ 0x00400780 e85bfeffff call sym.imp.strlen ; size_t strlen(const char *s)│ ╎ 0x00400785 4839c3 cmp rbx, rax│ ┌──< 0x00400788 733d jae 0x4007c7│ │╎ 0x0040078a 8b45c0 mov eax, dword [var_40h]│ │╎ 0x0040078d 8d500a lea edx, [rax + 0xa]│ │╎ 0x00400790 8b45c0 mov eax, dword [var_40h]│ │╎ 0x00400793 4898 cdqe│ │╎ 0x00400795 0fb680a01060. movzx eax, byte [rax + obj.s] ; [0x6010a0:1]=99 ; "c61b68366edeb7bdce3c6820314b7498"│ │╎ 0x0040079c 89c1 mov ecx, eax│ │╎ 0x0040079e 8b45c0 mov eax, dword [var_40h]│ │╎ 0x004007a1 83e001 and eax, 1│ │╎ 0x004007a4 85c0 test eax, eax│ ┌───< 0x004007a6 7407 je 0x4007af│ ││╎ 0x004007a8 b801000000 mov eax, 1│ ┌────< 0x004007ad eb05 jmp 0x4007b4│ │││╎ ; CODE XREF from main @ 0x4007a6│ │└───> 0x004007af b8ffffffff mov eax, 0xffffffff ; -1│ │ │╎ ; CODE XREF from main @ 0x4007ad│ └────> 0x004007b4 01c8 add eax, ecx│ │╎ 0x004007b6 89c1 mov ecx, eax│ │╎ 0x004007b8 4863c2 movsxd rax, edx│ │╎ 0x004007bb 8888e0106000 mov byte [rax + obj.t], cl ; [0x6010e0:1]=83 ; "SharifCTF{????????????????????????????????}"│ │╎ 0x004007c1 8345c001 add dword [var_40h], 1│ │└─< 0x004007c5 ebae jmp 0x400775│ │ ; CODE XREF from main @ 0x400788│ └──> 0x004007c7 48b82f746d70. movabs rax, 0x616c662f706d742f ; '/tmp/fla'│ 0x004007d1 488945d0 mov qword [filename], rax│ 0x004007d5 c745d8672e74. mov dword [var_28h], 0x78742e67 ; 'g.tx'│ 0x004007dc 66c745dc7400 mov word [var_24h], 0x74 ; 't' ; 116│ 0x004007e2 488d45d0 lea rax, [filename]│ 0x004007e6 be74094000 mov esi, 0x400974 ; const char *mode│ 0x004007eb 4889c7 mov rdi, rax ; const char *filename│ 0x004007ee e85dfeffff call sym.imp.fopen ; file*fopen(const char *filename, const char *mode)│ 0x004007f3 488945c8 mov qword [stream], rax│ 0x004007f7 488b45c8 mov rax, qword [stream]│ 0x004007fb ba20116000 mov edx, obj.u ; 0x601120 ; "*******************************************" ; ...│ 0x00400800 be76094000 mov esi, 0x400976 ; const char *format│ 0x00400805 4889c7 mov rdi, rax ; FILE *stream│ 0x00400808 b800000000 mov eax, 0│ 0x0040080d e80efeffff call sym.imp.fprintf ; int fprintf(FILE *stream, const char *format, ...)│ 0x00400812 c745c4000000. mov dword [var_3ch], 0│ ; CODE XREF from main @ 0x4008b0│ ┌─> 0x00400819 8b45c4 mov eax, dword [var_3ch]│ ╎ 0x0040081c 4863d8 movsxd rbx, eax│ ╎ 0x0040081f bfe0106000 mov edi, obj.t ; 0x6010e0 ; "SharifCTF{????????????????????????????????}" ; const char *s│ ╎ 0x00400824 e8b7fdffff call sym.imp.strlen ; size_t strlen(const char *s)│ ╎ 0x00400829 4839c3 cmp rbx, rax│ ┌──< 0x0040082c 0f8383000000 jae 0x4008b5│ │╎ 0x00400832 8b45c4 mov eax, dword [var_3ch]│ │╎ 0x00400835 4898 cdqe│ │╎ 0x00400837 8b0485601160. mov eax, dword [rax*4 + obj.p] ; [0x601160:4]=30│ │╎ 0x0040083e 4863c8 movsxd rcx, eax│ │╎ 0x00400841 488b45c8 mov rax, qword [stream]│ │╎ 0x00400845 ba00000000 mov edx, 0 ; int whence│ │╎ 0x0040084a 4889ce mov rsi, rcx ; long offset│ │╎ 0x0040084d 4889c7 mov rdi, rax ; FILE *stream│ │╎ 0x00400850 e8ebfdffff call sym.imp.fseek ; int fseek(FILE *stream, long offset, int whence)│ │╎ 0x00400855 8b45c4 mov eax, dword [var_3ch]│ │╎ 0x00400858 4898 cdqe│ │╎ 0x0040085a 8b0485601160. mov eax, dword [rax*4 + obj.p] ; [0x601160:4]=30│ │╎ 0x00400861 4898 cdqe│ │╎ 0x00400863 0fb680e01060. movzx eax, byte [rax + obj.t] ; [0x6010e0:1]=83 ; "SharifCTF{????????????????????????????????}"│ │╎ 0x0040086a 0fbec0 movsx eax, al│ │╎ 0x0040086d 488b55c8 mov rdx, qword [stream]│ │╎ 0x00400871 4889d6 mov rsi, rdx ; FILE *stream│ │╎ 0x00400874 89c7 mov edi, eax ; int c│ │╎ 0x00400876 e885fdffff call sym.imp.fputc ; int fputc(int c, FILE *stream)│ │╎ 0x0040087b 488b45c8 mov rax, qword [stream]│ │╎ 0x0040087f ba00000000 mov edx, 0 ; int whence│ │╎ 0x00400884 be00000000 mov esi, 0 ; long offset│ │╎ 0x00400889 4889c7 mov rdi, rax ; FILE *stream│ │╎ 0x0040088c e8affdffff call sym.imp.fseek ; int fseek(FILE *stream, long offset, int whence)│ │╎ 0x00400891 488b45c8 mov rax, qword [stream]│ │╎ 0x00400895 ba20116000 mov edx, obj.u ; 0x601120 ; "*******************************************" ; ...│ │╎ 0x0040089a be76094000 mov esi, 0x400976 ; const char *format│ │╎ 0x0040089f 4889c7 mov rdi, rax ; FILE *stream│ │╎ 0x004008a2 b800000000 mov eax, 0│ │╎ 0x004008a7 e874fdffff call sym.imp.fprintf ; int fprintf(FILE *stream, const char *format, ...)│ │╎ 0x004008ac 8345c401 add dword [var_3ch], 1│ │└─< 0x004008b0 e964ffffff jmp 0x400819│ │ ; CODE XREF from main @ 0x40082c│ └──> 0x004008b5 488b45c8 mov rax, qword [stream]│ 0x004008b9 4889c7 mov rdi, rax ; FILE *stream│ 0x004008bc e80ffdffff call sym.imp.fclose ; int fclose(FILE *stream)│ 0x004008c1 488d45d0 lea rax, [filename]│ 0x004008c5 4889c7 mov rdi, rax ; const char *filename│ 0x004008c8 e8f3fcffff call sym.imp.remove ; int remove(const char *filename)│ 0x004008cd b800000000 mov eax, 0│ 0x004008d2 488b5de8 mov rbx, qword [canary]│ 0x004008d6 6448331c2528. xor rbx, qword fs:[0x28]│ ┌─< 0x004008df 7405 je 0x4008e6│ │ 0x004008e1 e80afdffff call sym.imp.__stack_chk_fail ; void __stack_chk_fail(void)│ │ ; CODE XREF from main @ 0x4008df│ └─> 0x004008e6 4883c438 add rsp, 0x38│ 0x004008ea 5b pop rbx│ 0x004008eb 5d pop rbp└ 0x004008ec c3 ret
px命令查看十六进制内容pxoffset - 0 1 2 3 4 5 6 7 8 9 A B C D E F 0123456789ABCDEF0x00400756 5548 89e5 5348 83ec 3864 488b 0425 2800 UH..SH..8dH..%(.0x00400766 0000 4889 45e8 31c0 c745 c000 0000 008b ..H.E.1..E......0x00400776 45c0 4863 d8bf a010 6000 e85b feff ff48 E.Hc....`..[...H0x00400786 39c3 733d 8b45 c08d 500a 8b45 c048 980f 9.s=.E..P..E.H..0x00400796 b680 a010 6000 89c1 8b45 c083 e001 85c0 ....`....E......0x004007a6 7407 b801 0000 00eb 05b8 ffff ffff 01c8 t...............0x004007b6 89c1 4863 c288 88e0 1060 0083 45c0 01eb ..Hc.....`..E...0x004007c6 ae48 b82f 746d 702f 666c 6148 8945 d0c7 .H./tmp/flaH.E..0x004007d6 45d8 672e 7478 66c7 45dc 7400 488d 45d0 E.g.txf.E.t.H.E.0x004007e6 be74 0940 0048 89c7 e85d feff ff48 8945 [email protected]...]...H.E0x004007f6 c848 8b45 c8ba 2011 6000 be76 0940 0048 .H.E.. .`[email protected]0x00400806 89c7 b800 0000 00e8 0efe ffff c745 c400 .............E..0x00400816 0000 008b 45c4 4863 d8bf e010 6000 e8b7 ....E.Hc....`...0x00400826 fdff ff48 39c3 0f83 8300 0000 8b45 c448 ...H9........E.H0x00400836 988b 0485 6011 6000 4863 c848 8b45 c8ba ....`.`.Hc.H.E..0x00400846 0000 0000 4889 ce48 89c7 e8eb fdff ff8b ....H..H........
iz命令可以查看程序中的字符串[0x00400756]> iz[Strings]nth paddr vaddr len size section type string―――――――――――――――――――――――――――――――――――――――――――――――――――――――0 0x000010a0 0x006010a0 32 33 .data ascii c61b68366edeb7bdce3c6820314b74981 0x000010e0 0x006010e0 43 44 .data ascii SharifCTF{????????????????????????????????}2 0x00001120 0x00601120 43 44 .data ascii *******************************************
[0x00400756]> axt 0x6010a0main 0x40077b [DATA] mov edi, obj.smain 0x400795 [DATA] movzx eax, byte [rax + obj.s]
vv命令进入
r2 -d -A ./program命令来进入调试器$ r2 -d -A ./e3dd9674429f4ce1a25c08ea799fc027[x] Analyze all flags starting with sym. and entry0 (aa)[x] Analyze function calls (aac)[x] Analyze len bytes of instructions for references (aar)[x] Finding and parsing C++ vtables (avrr)[x] Skipping type matching analysis in debugger mode (aaft)[x] Propagate noreturn information (aanr)[x] Use -AA or aaaa to perform additional experimental analysis.[0x7f8186b18050]>
db：断点，db后可以跟函数名或者地址dbi：查看已有断点dc：运行程序dbt：查看堆栈dr：查看寄存器
$ r2 -d -A ./e3dd9674429f4ce1a25c08ea799fc027[x] Analyze all flags starting with sym. and entry0 (aa)[x] Analyze function calls (aac)[x] Analyze len bytes of instructions for references (aar)[x] Finding and parsing C++ vtables (avrr)[x] Skipping type matching analysis in debugger mode (aaft)[x] Propagate noreturn information (aanr)[x] Use -AA or aaaa to perform additional experimental analysis.[0x7f53c8464050]> db main[0x7f53c8464050]> dbi0 0x00400756 E:1 T:0[0x7f53c8464050]> dchit breakpoint at: 0x400756[0x00400756]> dbt0 0x400756 sp: 0x0 0 [main] main entry.init0+38[0x00400756]> drrax = 0x00400756rbx = 0x004008f0rcx = 0x7f53c8443738rdx = 0x7ffcee042568r8 = 0x00000000r9 = 0x7f53c84731f0r10 = 0xfffffffffffffb8cr11 = 0x7f53c829c730r12 = 0x00400660r13 = 0x00000000r14 = 0x00000000r15 = 0x00000000rsi = 0x7ffcee042558rdi = 0x00000001rsp = 0x7ffcee042468rbp = 0x00000000rip = 0x00400756rflags = 0x00000246orax = 0xffffffffffffffff
r2pm -l命令查看当前插件，r2的插件有很多，这里使用r2dec反编译插件来实现对程序的反编译，r2pm -install r2dec来安装，安装完成后可以直接在r2中使用-A加载程序，然后使用r2dec反汇编程序，反汇编的命令是pddar2 -A ./e3dd9674429f4ce1a25c08ea799fc027Analyze all flags starting with sym. and entry0 (aa)Analyze function calls (aac)Analyze len bytes of instructions for references (aar)Check for vtablesType matching analysis for all functions (aaft)Propagate noreturn informationUse -AA or aaaa to perform additional experimental analysis.s mainpddaassembly | /* r2dec pseudo code output *//* ./e3dd9674429f4ce1a25c08ea799fc027 @ 0x400756 */#include <stdint.h>(fcn) main () | int32_t main (void) {int64_t var_40h;int64_t var_3ch;file* stream;char * filename;int64_t var_28h;int64_t var_24h;int64_t canary;0x00400756 push rbp |0x00400757 mov rbp, rsp |0x0040075a push rbx |0x0040075b sub rsp, 0x38 |0x0040075f mov rax, qword fs:[0x28] | rax = *(fs:0x28);0x00400768 mov qword [rbp - 0x18], rax | *((rbp - 0x18)) = rax;0x0040076c xor eax, eax | eax = 0;0x0040076e mov dword [rbp - 0x40], 0 | *((rbp - 0x40)) = 0;do {0x00400775 mov eax, dword [rbp - 0x40] | eax = *((rbp - 0x40));0x00400778 movsxd rbx, eax | rbx = (int64_t) eax;0x0040077b mov edi, 0x6010a0 |0x00400780 call 0x4005e0 | rax = strlen ("c61b68366edeb7bdce3c6820314b7498");0x00400785 cmp rbx, rax |if (rbx >= rax) {0x00400788 jae 0x4007c7 | goto label_0;}0x0040078a mov eax, dword [rbp - 0x40] | eax = *((rbp - 0x40));0x0040078d lea edx, [rax + 0xa] | edx = rax + 0xa;0x00400790 mov eax, dword [rbp - 0x40] | eax = *((rbp - 0x40));0x00400793 cdqe | rax = (int64_t) eax;0x00400795 movzx eax, byte [rax + 0x6010a0] | eax = *((rax + obj.s));0x0040079c mov ecx, eax | ecx = eax;0x0040079e mov eax, dword [rbp - 0x40] | eax = *((rbp - 0x40));0x004007a1 and eax, 1 | eax &= 1;0x004007a4 test eax, eax |if (eax != 0) {0x004007a6 je 0x4007af |0x004007a8 mov eax, 1 | eax = 1;0x004007ad jmp 0x4007b4 |} else {0x004007af mov eax, 0xffffffff | eax = 0xffffffff;}0x004007b4 add eax, ecx | eax += ecx;0x004007b6 mov ecx, eax | ecx = eax;0x004007b8 movsxd rax, edx | rax = (int64_t) edx;0x004007bb mov byte [rax + 0x6010e0], cl | *((rax + obj.t)) = cl;0x004007c1 add dword [rbp - 0x40], 1 | *((rbp - 0x40))++;0x004007c5 jmp 0x400775 |} while (1);label_0:0x004007c7 movabs rax, 0x616c662f706d742f | rax = 0x616c662f706d742f;0x004007d1 mov qword [rbp - 0x30], rax | *((rbp - 0x30)) = rax;0x004007d5 mov dword [rbp - 0x28], 0x78742e67 | *((rbp - 0x28)) = 0x78742e67;0x004007dc mov word [rbp - 0x24], 0x74 | *((rbp - 0x24)) = 0x74;0x004007e2 lea rax, [rbp - 0x30] | rax = rbp - 0x30;0x004007e6 mov esi, 0x400974 |0x004007eb mov rdi, rax |0x004007ee call 0x400650 | rax = fopen (rax, 0x400974);0x004007f3 mov qword [rbp - 0x38], rax | *((rbp - 0x38)) = rax;0x004007f7 mov rax, qword [rbp - 0x38] | rax = *((rbp - 0x38));0x004007fb mov edx, 0x601120 | edx = "*******************************************";0x00400800 mov esi, 0x400976 |0x00400805 mov rdi, rax |0x00400808 mov eax, 0 | eax = 0;0x0040080d call 0x400620 | fprintf (rax, 0x400976);0x00400812 mov dword [rbp - 0x3c], 0 | *((rbp - 0x3c)) = 0;do {0x00400819 mov eax, dword [rbp - 0x3c] | eax = *((rbp - 0x3c));0x0040081c movsxd rbx, eax | rbx = (int64_t) eax;0x0040081f mov edi, 0x6010e0 |0x00400824 call 0x4005e0 | rax = strlen ("SharifCTF{????????????????????????????????}");0x00400829 cmp rbx, rax |if (rbx >= rax) {0x0040082c jae 0x4008b5 | goto label_1;}0x00400832 mov eax, dword [rbp - 0x3c] | eax = *((rbp - 0x3c));0x00400835 cdqe | rax = (int64_t) eax;0x00400837 mov eax, dword [rax*4 + 0x601160] | eax = *((rax*4 + obj.p));0x0040083e movsxd rcx, eax | rcx = (int64_t) eax;0x00400841 mov rax, qword [rbp - 0x38] | rax = *((rbp - 0x38));0x00400845 mov edx, 0 |0x0040084a mov rsi, rcx |0x0040084d mov rdi, rax |0x00400850 call 0x400640 | fseek (rax, rcx, 0);0x00400855 mov eax, dword [rbp - 0x3c] | eax = *((rbp - 0x3c));0x00400858 cdqe | rax = (int64_t) eax;0x0040085a mov eax, dword [rax*4 + 0x601160] | eax = *((rax*4 + obj.p));0x00400861 cdqe | rax = (int64_t) eax;0x00400863 movzx eax, byte [rax + 0x6010e0] | eax = *((rax + obj.t));0x0040086a movsx eax, al | eax = (int32_t) al;0x0040086d mov rdx, qword [rbp - 0x38] | rdx = *((rbp - 0x38));0x00400871 mov rsi, rdx |0x00400874 mov edi, eax |0x00400876 call 0x400600 | fputc (eax, *((rbp - 0x38)));0x0040087b mov rax, qword [rbp - 0x38] | rax = *((rbp - 0x38));0x0040087f mov edx, 0 | edx = 0;0x00400884 mov esi, 0 |0x00400889 mov rdi, rax |0x0040088c call 0x400640 | fseek (rax, 0, edx);0x00400891 mov rax, qword [rbp - 0x38] | rax = *((rbp - 0x38));0x00400895 mov edx, 0x601120 | edx = "*******************************************";0x0040089a mov esi, 0x400976 |0x0040089f mov rdi, rax |0x004008a2 mov eax, 0 | eax = 0;0x004008a7 call 0x400620 | fprintf (rax, 0x400976);0x004008ac add dword [rbp - 0x3c], 1 | *((rbp - 0x3c))++;0x004008b0 jmp 0x400819 |} while (1);label_1:0x004008b5 mov rax, qword [rbp - 0x38] | rax = *((rbp - 0x38));0x004008b9 mov rdi, rax |0x004008bc call 0x4005d0 | fclose (*((rbp - 0x38)));0x004008c1 lea rax, [rbp - 0x30] | rax = rbp - 0x30;0x004008c5 mov rdi, rax |0x004008c8 call 0x4005c0 | remove (rax);0x004008cd mov eax, 0 | eax = 0;0x004008d2 mov rbx, qword [rbp - 0x18] | rbx = *((rbp - 0x18));0x004008d6 xor rbx, qword fs:[0x28] | rbx ^= *(fs:0x28);if (*((rbp - 0x3c)) != 0) {0x004008df je 0x4008e6 |0x004008e1 call 0x4005f0 | stack_chk_fail ();}0x004008e6 add rsp, 0x38 |0x004008ea pop rbx |0x004008eb pop rbp |0x004008ec ret | return rax;}
0x04 题目实例
int __cdecl main(int argc, const char **argv, const char **envp){char v3; // alint i; // [rsp+0h] [rbp-40h]int j; // [rsp+4h] [rbp-3Ch]FILE *stream; // [rsp+8h] [rbp-38h]char filename[24]; // [rsp+10h] [rbp-30h] BYREFunsigned __int64 v9; // [rsp+28h] [rbp-18h]v9 = __readfsqword(0x28u);for ( i = 0; i < strlen(s); ++i ){if ( (i & 1) != 0 )v3 = 1;elsev3 = -1;*(&t + i + 10) = s[i] + v3;}strcpy(filename, "/tmp/flag.txt");stream = fopen(filename, "w");fprintf(stream, "%sn", u);for ( j = 0; j < strlen(&t); ++j ){fseek(stream, p[j], 0);fputc(*(&t + p[j]), stream);fseek(stream, 0LL, 0);fprintf(stream, "%sn", u);}fclose(stream);remove(filename);return 0;}
0x05 总结
参考文章：https://wizardforcel.gitbooks.io/100-gdb-tips/content/print-registers.htmlhttps://linuxtools-rst.readthedocs.io/zh_CN/latest/tool/gdb.htmlhttps://linux.cn/article-13074-1.html
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Tide安全团队正式成立于2019年1月，是新潮信息旗下以互联网攻防技术研究为目标的安全团队，团队致力于分享高质量原创文章、开源安全工具、交流安全技术，研究方向覆盖网络攻防、系统安全、Web安全、移动终端、安全开发、物联网/工控安全/AI安全等多个领域。
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原文始发于微信公众号（Tide安全团队）：动态调试elf文件的几种方法
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